Erm, maybe that SQL statement is confusing, simplify that SQL statement first such that LINQ to SQL can recognise.

Whenever i see "value = MAX(value)", reminds me of the cookie/chocolate chip solution in chapter 4 still fresh on my mind altho thats for Linq to Object

The objective is clear.
U have a Box of Cookies (diekenMerken) ,
there's cookies (DKMLD) of different shape (GDRID) ,
every cookies have chocolate chips (DKMTIJDSTIP).
U want to ignore all shapes except Square and find the cookies with the most chocolate chips among the Squared Cookies